Re: [Xenomai-help] VM killer

[Jan Kiszka <jan.kiszka@domain.hid>]

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Gilles Chanteperdrix wrote:
> Daniel Schnell wrote:
>> Hi,
>>  
>> I know this is somewhat not related to Xenomai. But as I encountered
>> this while actually testing the memory allocation with Xenomai, maybe
>> there is some common sense here, as there are many people having to do
>> with embedded systems, where something like that matters.
>>  
>> Everytime the system comes to its limits and some process uses up all
>> the memory the vm systems kills (more or less randomly) one or more
>> processes. Even system processes. I would really like to get rid of this
>> behaviour, but having disabled CONFIG_OOM_KILLER inside the linux kernel
>> doesn't help.
>>  
>> I use ELDK4.0 with 2.4.25 Denx Kernel.
>>  
>> Any hints ?
> 
> There is no way the system can run properly if there is not enough RAM.
> Add some RAM to your board, or decrease the memory used by applications.

Having a means to avoid that your critical process gets killed
accidentally because some uncritical one decided to suck up all system
resources is, IMO, a very legitimate use case. On 2.6, where there is no
CONFIG_OOM_KILLER, you can play with /proc/<pid>/oom_adj and make your
process "unattractive" to the OOM killer (set to -17). On older kernels
you also had to include any parent processes in this protection. I think
this was fixed meanwhile.

But I wonder why there should be no effect of CONFIG_OOM_KILLER on 2.4.
Forgot to replay the updated kernel binaries?

Jan


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